The color of screw cap is available Red, Green, Yellow and Blue. The septa of 9-425 HPLC Screw Vial is made of PTFE and silicone to ensure proper function and be pre-slit to easy needle penetration. 9-425 HPLC Screw Vial is produce by Aijiren, which is one of the largest chromatography consumable manufacturer in south of China.